:root {
  --bg: #ffffff;
  --text: #111111;
  --card: #f9f9f9;
  --link: #1e88e5;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #121212;
    --text: #ffffff;
    --card: #1f1f1f;
    --link: #90caf9;
  }
}
body {
  margin: 0;
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  background-color: var(--bg);
  color: var(--text);
  display: flex;
  flex-direction: column;  /* ✅ Stack header, content, etc. vertically */
  min-height: 100vh;
}
.animated-banner {
  width: 100%;
  background: linear-gradient(-45deg, #2196f3, #21cbf3, #1e88e5, #1a237e);
  background-size: 400% 400%;
  animation: gradientBG 8s ease infinite;
  padding: 50px 20px;
  text-align: center;
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
}

.animated-banner h1 {
  color: #ffffff;
  font-size: 3rem;
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  margin: 0;
  letter-spacing: 1px;
  animation: fadeInUp 1.2s ease-out;
}

/* Gradient background animation */
@keyframes gradientBG {
  0% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
  100% { background-position: 0% 50%; }
}

/* Fade-in animation for text */
@keyframes fadeInUp {
  0% {
    opacity: 0;
    transform: translateY(30px);
  }
  100% {
    opacity: 1;
    transform: translateY(0);
  }
}


.logo {
  font-size: 24px;
  font-weight: bold;
  color: #fff;
}

.nav-links {
  list-style: none;
  display: flex;
  gap: 20px;
}

.nav-links li a {
  color: #090000;
  text-decoration: none;
  font-weight: 500;
}

.nav-links li a:hover {
  color: #00aced;
}

/* Mobile menu toggle */
.menu-toggle {
  display: none;
  font-size: 24px;
  cursor: pointer;
  color: white;
}

/* Dropdown */
.dropdown-content {
  display: none;
  position: absolute;
  background-color: white;
  padding: 10px 0;
  box-shadow: 0 4px 10px rgba(0, 0, 0, 0.1);
}

.dropdown:hover .dropdown-content {
  display: block;
}

.dropdown-content li {
  padding: 8px 20px;
}

.dropdown-content li a {
  color: #333;
  font-weight: normal;
}

.dropdown-content li a:hover {
  color: #007bff;
}


  .highlight {
      font-weight: bold;
      color: #2d3436;
    }

.content {
  flex-grow: 1;
  padding: 30px;
  background-color: var(--bg);
}

.topic-card {
  background: var(--card);
  border-radius: 12px;
  padding: 20px;
  margin-bottom: 20px;
  box-shadow: 0 3px 8px rgba(0, 0, 0, 0.05);
}

.topic-card h3 {
  margin-top: 0;
}

.navigation {
  display: flex;
  justify-content: space-between;
  margin-top: 20px;
}

.navigation a {
  background: var(--link);
  color: white;
  padding: 8px 16px;
  text-decoration: none;
  border-radius: 6px;
  transition: background 0.3s ease;
}

.navigation a:hover {
  background: #1565c0;
}

@media screen and (max-width: 768px) {
  body {
    flex-direction: column;
  }

  nav {
    width: 100%;
    box-shadow: none;
  }

  .content {
    padding: 20px;
  }
}
 table {
      width: 100%;
      border-collapse: collapse;
      background-color: #fff;
      border: 2px solid #3498db;
      box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    }
    th, td {
      padding: 16px;
      border: 1px solid #3498db;
      text-align: left;
      vertical-align: top;
    }
    th {
      background-color: #2980b9;
      color: #fff;
      font-size: 18px;
    }
    tr:nth-child(even) {
      background-color: #f0f8ff;
    }
    tr:hover {
      background-color: #d6eaf8;
    }
     .video-container {
    position: relative;
    width: 100%;
    max-width: 560px;
    aspect-ratio: 16 / 9; /* Modern responsive aspect ratio */
    margin: 20px auto;
  }

  .video-container iframe {
    width: 100%;
    height: 100%;
    border: none;
    display: block;
  }